Charles Ellicott Commentary Revelation 7:11

"And all the angels were standing round about the throne, and [about] the elders and the four living creatures; and they fell before the throne on their faces, and worshipped God," — Revelation 7:11 (ASV)

And all the angels... — Translate, And all the angels were standing around the throne, and the elders, and the four living beings ... saying, Amen. The great concourse of angels—those among whom there has been joy in heaven when a sinner has repented—now add their “Amen” to the cry of the redeemed, and then raise the sevenfold ascription of praise—

“Amen!
The blessing, and the glory, and the wisdom,
And the thanksgiving,
And the honour, and the power, and the strength,
(Is) to our God to the ages of the ages.
Amen!”

The sevenfold form of the doxology, which implies a divine completeness, is appropriate to this vision, which shows us the close of the Church’s agony, and is in itself a slight indication that the view which would limit the seals to some short period of Church history is incorrect, as it is assuredly inadequate.